Carburetor



Patented Oct. 2 1,- l193() ,iran STA GEORGE M. BICMELL, OF-ST. LOUIS, MISSOURI, ASSIGNOR TO CABTEB'CARBUBETOB A CORPORATION, OF ST. LOUIS, MISSOURI, A CORPORATION OF DELAWARE cannunn'ron Application led November 16, 1928. v Serial No. 319,945.

present designs of internal combustion engines, it has been found possible to operate with a lean mixture throughout the throttle valve openings used under ordinary operating conditions; a rich mixture being desirable only during the starting and when the throttle is open fully or nearly so. In carburetors provided with a starting nozzle or jet it is therefore desirable t adjust the carburetor to provide a lean 'mixture during 'the usual openings of the carburetor throttle valve and `to provide a means for changinor the lean mixture to a rich mixture when the throttle valve is fully open or nearly so. It is there'- fore an object of this invention to provide means for increasing the richness of the mixture supplied by the carburetor when the throttle valve of the carburetor is opened a predetermined amount and for providing a lean mixture when the throttle valve is closed to less than the predetermined opening. It is also an object of this invention to provide a control for the calibrated orifice of the fuel nozzle which gives an effective opening of one size throughout a predetermined range of the throttle valve opening and gives an opening of another size throughout another range of the throttle valve opening.

With these and other objects in view, as will appear more 'fully hereinafter, the invention consists substantially in the construction, combination, location and relative arrangement of the parts, all as will be more fully herein set-forth, as shown in the accompanying drawings and iinally pointed out in the appended claims.

In the drawings:

Figure 1 is a central vertical section of a l -1s constricted as at 50, and mounted for recarburetor provided with means for controlling the metering orifice of the fuel nozzle in accordance with this invention; and

Fig. 2 is a vertical section drawn to a larger scale of the fuel nozzle, bowl plug and meteringlpin shown in Fig4 1. Y

the drawings t e invention is shown in connection with a carburetor comprising a body or casing 1 having an air inlet 2 and a mixture outlet 4. The mixture outlet is providedwith a venturi 6 and a throttle valve 8; the throttle valve 8 being mounted on a shaft 10 journaled in the walls of the casing 1. The casing 1 is formed with an extension 12 directed oppositely to the mixture outlet 4 and provided with an irregularly shaped opening 14 therethrough; the enlargedouter end of the opening being closed by a plug 16 threaded in the opening 14 and securlng the bowl 18 to the casing 1. The bowl 18 forms the float chamber 20 in which is mounted the float 22 controlling the supply of fuel to the chamber 20 by means of a valve (not shown). In the enlarged -outer end of the opening 14 above the plug 16 there is mounted. a 'fuel nozzle 24 which projects beyond theinner or upper end of the opening 14. In the enlarged upper end of the opening 14 is mounted a standpipe 26 which surrounds the upper end of the nozzl#` 24 and extends into the lower end of the venturi 6. Surrounding the standpipe 26 is a choke valve 28 operated by an arm 30 on ashaft 32 and controlling not only the admission of air to the venturi 6 but the admission of air through the ports 34 to the standpipe 26. The chamber formed b the opening 14 is connected with the iioat c amber 20 by means of a lpassage 36 and by means of a passage 38 with an idling tube or jet 40 which communicates through a port .42 with the mixture outlet 4 in the region of the throttle valve 8. The base of the standpipe 26 is rovided with an opening 46 through which communication is established between the air inlet 2 and the chamber formed by the o ening 14, and the standpipe 26 is provide with an opening 48 establishing communication between the air inlet 2 and the interior of the standpipe 26.

The passage 49 through the fuel nozzle 24 at 58; the length of the portion 60 of greater diameter being such that in the usual operation positions of the throttle valve 8 the portion 60 enters theconstricted opening 50 in the fuel passage 49 of the nozzle 24 and determines the effective opening of the nozzle 24. When the valve 8 is approximately seveneighths open, the portion 60leaves the constricted opening 50, after which the portion 58 of less diameter determines the effective opening in the constricted'portion 50 and gives a larger eective opening inthe constricted portion of thel fuel nozzle. It will be noted thatthe plug 16 is provided with a recess 62 in which the reduced portion 58 of the metering pin'fits; the plug 16 engaging the reduced porton 58 of the metering pin and serving to guide the metering pin and prevent wear of the fuel nozzle at the constricted portion 50 and change in the calibration of the opening.

From the above it is seen that during the usual' opening of the throttle valve 8' a fuel opening of one size is provided, and that as soon as the opening of the throttle valve 8 exceedsa predetermined amount the ortion 58 of the metering pin is brought to t e constricted portionl 50 and a fuel opening of greater area provided permitting. of increased flow of fuel to the nozzle and-providing a richer mixture. It will of course be' understood that the point at which the greater effective area of the nozzle 24 becomes operative may be varied by changing the relative proportions ofthe portions 58 and 60 of the metering in 52. e

The drawings erein disclose the preferred embodiment of the invention, but 1t is to be understood that they are merely by wafy of example and that various changes in orm and proportions of the device ma be made within the scope of the appended claims without departing from the spirit of the invention. i

What is claimedis:

` 1. In a carburetor, a body member having a bore, a fuel nozzle threaded into said bore having a. fuel passage formed with a con- Vstricted portion therein,A a metering pin 50.

mounted in said nozzle and determining the effective opening of the-constricted ortion of said nozzle, anda guide member or said metering pin also threaded into said bore.

2. As an article of manufacture, a combined bowl retaining nut and metering rod protector for carburetors comprising a body member havin a screw threaded portion adapted to be t readed into a corresponding screw threaded bore in the body o a carburetor, said body member having a flange at the inner end ofsaid thread, said Hangs being adapted to en age the bowl of t e carburetor and to hol it tightly against the end of the body member, and a longitudinal bore in said body member, said bore being open at the inner end to receive and protect the metering rod of the carburetor, said bore being closed at its outer end to prel vent the escape of fuel from the carburetor.

3. In a carburetor, a main body member having a downwardly extending portion, an annular seat surrounding said downwardly extending portion, a cup-shaped bowl having an upper rim adapted to engage Asaid seat, the bottom of said bowl having a concentric perforation therein and being adapted tobe held against the end of said downward extension, a. vertically extending opening in saidmain body member, a rod extending through said opening and downwardlythrogh the perforation in the'bowl, and a single means forming a housing for the extension of said rod and retaining said bowl inposition.

4. In a device of the class described having a main body member, anvannular seat on said body member, a cup shapedv bowl having its rim engaging said seat, an extension ofxsaid .body member substantially co-axial with said seat and extending into said bowl; a longitudinal passageway in said extension, a transverse passageway providing communication between said bowl and said longitudinal passageway, vmeans forming a restricted portion in said longitudinal passagewa a longitudinal moveable control rod exten ing through thefpassageway to control the effective area of the restricted portion and protruding be ond the end of said extension, screw threav s inthe end of said extension, and a perforation in the end 4of said bowl registering with said thread; the improvement comprising a screw threaded nut having a flange adapted to engage the end of said bowl and hold thevsame firmly in place when the nut is screwed into the said extension, said nut having an axial bore open only at its inner end for housing and protecting the protruding end of said control rod.

5. In a carburetor of the type having a main body member having a passa eway therethru, a screw threaded enlarge portion at one end of said passageway, a nozzle threaded into said enlarged portion, a metering orifice in said nozzle, a cup shaped bowl having an openingin its bottom, said bowl being mounted in surrounding relation to the end of the body member Vand with the opening in registration withthe end of the enlarged passageway, a bore in thebodymember connecting the enlarged portion of the passageway With the interior of the bowl, and a longitudinally movable control rod extending thru the passageway and the metering orifice to control the same, the improvement comprising a member passing thru the perforation-in thebowl and screw threaded into the enlarged portion of said passageway to close the same, said last named member having'a. ange for holding the bowl firmly against the end of the'body member, and having a concentriebore tore- 5 ceive the end of the rod.

In witness whereof I have hereunto set my hand.

GEORGE M. BICKNELL. 

